SOLUTION: 11. The distribution of annual earnings of all bank tellers with five years of experience is skewed negatively. This distribution has a mean of Birr 15,000 and a standard deviation

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Question 1120626: 11. The distribution of annual earnings of all bank tellers with five years of experience is skewed negatively. This distribution has a mean of Birr 15,000 and a standard deviation of Birr 2000. If we draw a random sample of 30 tellers, what is the probability that their earnings will average more than Birr 15,750 annually?
Required:
• Calculate µ and
• Calculate Z for
• Find the area covered by the interval
• Interpret the results

Answer by Boreal(15235) About Me  (Show Source):
You can put this solution on YOUR website!
z=(x bar-mean)/s/sqrt(n)
z>(15750-15000)/2000/sqrt (30)
z>750*sqrt(30)/2000
z>2.05
This probability is 0.0202
The likelihood of a random sample of size 30 of having a mean of 15,750 or greater is just over 2%.